Connecting element

ABSTRACT

Connection of two longitudinal sections (10, 22) that are at an angle to each other, each longitudinal section (10, 22) having two connecting sides (12) and two wall sides (14), where at least one connecting side (12) of each section (10, 22) exhibits a groove (24) that is undercut on both sides and on both sides of the undercut groove (24) an integral longitudinal flange (30). The first longitudinal section (10) exhibits a transversely cut section face, the end face (16) of the first longitudinal section (10) which is secured at an angle to a connecting side (12) of the second longitudinal section (22). The first longitudinal section (10) exhibits a recess (18) at its end (16) in which a connecting element (60), introduced into the groove-like recess (34) between the longitudinal flanges (30) in the second longitudinal section (22), engages--as a result of which the connecting element (60) forms a mechanical joint by virtue of fit with the end recess (10). A connecting mass (54) for sealing the joint or to achieve an exact fit mechanical joint may be provided between the connecting element (60) and the end recess (18) of the first longitudinal section (10) and/or between the connecting element (60) and the longitudinal flange (30) of the second longitudinal section (22). The connection is particularly suitable for assembly of frame-type structures of longitudinal sections (10, 22) for the superstructures of road and railway vehicles.

BACKGROUND OF THE INVENTION

The present invention relates to a connection between two longitudinalsections that are at an angle to each other, each section having twoconnecting sides and two wall sides, where at least one connecting sideof each longitudinal section exhibits a groove that is undercut on bothsides and an integral longitudinal flange on both sides of the undercutgroove, the first longitudinal section being cut transversely and thistransversely cut section face forms the end of the first longitudinalsection which is secured at an angle to a connecting side of the secondlongitudinal section. The invention relates further to a process formanufacturing the connection and the use of the connection.

Connections of the above mentioned kind are employed from example in theassembly of frame-type structures for vehicle superstructures e.g. onroad and railway vehicles. The structural components are usually made ofsteel, aluminum or plastic sections, complemented e.g. by shaped steelor aluminum sheets or panels of plastic or if desired plastic or glasssegments. Such structural components are in particular made of extrudedaluminum, plastic or steel sections.

Connection means for light metal sections utilizing shape and/orfriction joining are known. From the Swiss patent CH 627 982 connectionsbased on friction joining of metal sections with the aid of comerconnecting pieces are known especially for the assembly of frame-typestructures for superstructures of road and railway vehicles. Thedescribed comer connecting pieces feature integral spring like partsthat are introduced into undercut grooves in the metal sections andsecured by screws. The screw connections contain clamping pieces whichare introduced into the undercut grooves in the metal sections and thentilted into the undercut parts of the section.

In the connection described in CH 627 982 forces are transferred fromone section to the other essentially via the angle piece; often andespecially in the case of thin walled sections, this does not provideoptimum transfer of forces. Further, in many applications onelongitudinal section is often joined to the end of another cross-cutsection. In such cases it is necessary to have a clean dividing line atthe cut across the latter section. The subsequent working or machiningof the cut section end is time consuming and expensive. Further, thinwalled sections cannot be well sealed as e.g. filling with a fillermaterial is not possible because there is no proper contact at thejoint.

Described in patents DE, A, 38 23 941, GB, A, 919 135 and FR, A, 2 641809 are nodal joints of pairs of hollow longitudinal sections that arerectangular in cross-section, where the end of one section meets a longface of the other section. Thereby, a square shaped part is insertedinto undercuts on the outside of the second section and the end of thefirst section pushed over the square shaped part so that the squareshaped part engages in the end of the first section. The transfer offorces from one section to the other in this known connection isessentially via the outside of the section.

In order to prevent the first section from sliding in the axialdirection, the connection according to DE, A, 38 23 941 exhibitsdeformations in the section wall which engage the square shaped part inrecesses. In the case of GB, A, 919 315 and FR, A, 2 641 809 the sameeffect is achieved by friction, welding or by screwing the first sectionto the square shaped part.

The present state of the an is such that known connection means are notsuitable for joining the end of one longitudinal section e.g. of smallcross-section to the long side of another longitudinal section, as themechanical stability of such a connection is normally inadequate.Further, in the case of known connections, the end of the firstlongitudinal section lies on the long side of the second longitudinalsection so that in such connections, in order to accommodate largeforces, the surfaces to be joined have to be of a very high standard.

SUMMARY OF THE INVENTION

The object of the present invention is to create a connection between apair of longitudinal sections at an angle to each other, whereby theabove mentioned disadvantages are avoided and in particular requires nosubsequent working of the cross-cut section and permits tight joints tobe made also with thin walled sections.

That object is achieved by way of the invention in that the firstlongitudinal section exhibits a recess at its end and a connectingelement, that is introduced into the groove-like recess between thelongitudinal flanges in the second longitudinal section, engages in thisrecess as a result of which the connecting element forms a mechanicaljoint by virtue of fit with the end recess.

The connecting element comes to rest between the end face of the firstlongitudinal section and a connecting side of the second longitudinalsection, the connecting element having a positively shaped configurationand the first longitudinal section an end recess with a negativelyshaped configuration. The positively shaped configuration of theconnecting element and the negatively shaped configuration resultingfrom the end recess complement each other and in doing so provide amechanical joint by virtue of shape by means of which forces aretransferred from one section to the other via the outer planes of thesection and via the inner end region of the first longitudinal section.In addition, by way of the connection according to the invention themanufacturing tolerances of the abutting faces compensate for eachother, which makes it possible to provide tight joints.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is explained in greater detail by way of examplewith the aid of FIGS. 1 to 4.

FIG. 1 shows a perspective view of a connection according to theinvention of two extruded sections that are perpendicular to each other;

FIG. 2 shows an exploded view of that shown in FIG. 1;

FIG. 3 shows various connecting elements in perspective view; and

FIG. 4 shows the end view of that shown in FIG. 1 with various kinds ofconnecting elements as seen along section IV--IV in FIG. 1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The longitudinal sections to be joined are normally made of steel,plastic or light metals e.g. aluminum or its alloys. The connectionspresented here are preferably used for joining extruded sections ofaluminum or its alloys.

The connection according to the invention are suitable for long sectionsthat preferably feature on one side, the so-called joining side, anundercut groove with a longitudinal opening and on both sides of theundercut groove an integral longitudinal flange. In the following, therecess formed in the longitudinal section as a result of the undercutgroove longitudinal flange will be referred to as the groove-likerecess. Also the sides of the section adjacent to the joining sides willbe referred to as the wall sides.

In a simple version of the longitudinal section the longitudinal flangesis part of the wall sides, the undercut of the undercut groove formingintegral strips. At a distance from the section strips struts may beprovided that on the side towards the strips frame in the undercutgroove.

It is preferred to join together longitudinal sections that have thesame cross-section. Preferred for the connection according to theinvention are longitudinal sections that exhibit on the undercut grooveintegral longitudinal flanges on the joining side that have the samespacing. In a simple longitudinal section in which the longitudinalflanges are part of the wall sides, the requirement of same spacing forthe flanges also the requirement for equal spacing for the wall sides.

For the connection according to the invention the longitudinal sectionsmay be a right angle (butt joint) or any desired acute angle (slopingjoint). Preferred, however, is the joining of two longitudinal sectionsat a right angle. If the sections to be joined have to be made with asloping joint, the end face of the first longitudinal section ispreferably prepared, instead of at right angles, such that the end faceforms the same angle as that which the end face forms with the secondlongitudinal section.

In the first longitudinal section, the end recess which is requiredaccording to the invention, may concern only a part of the end or thewhole of the end part lying between the wall sides of the first section.The end recess preferably concerns the whole of the end part lyingbetween the wall sides of the first section so that essentially thesection strips and if desired the section struts in the end region ofthe first section are affected by the end recess. Forming a recess atthe end of the first longitudinal section results in end flanges beingcreated at the recess, especially on the wall side. If the end recessconcerns the whole of the end region between the wall sides, then theend flange is formed by the projecting parts of the end wall of thefirst longitudinal section.

The end flanges formed by the end recess is preferably at least 2 mm inheight, in particular between 2 and 5 mm.

The end recess exhibits a negative curvature as seen in profile,preferably purely concave in form. Further, it is shaped in such amanner that, together with the positive profile of the connectingelement, it enables an interfacing shape-endowed mechanical connectionto be achieved by virtue of fit. The connecting element is preferablypurely convex in shape. However, the present invention also embracesconnections in which the end recess and the connecting element exhibite.g. a perfect tongue and groove type of fit in order e.g. to improvethe tightness of the connection or the transfer of forces there. In thepresent text the expression, shape-endowed mechanical connection, is notto be understood only as providing an end recess with an exact fit tothe outward projecting part of the connecting element; more importantly,to be understood by this are also the essentially exact fit connectionsbetween the above mentioned parts that e.g. permit a tightly sealed ormechanical, shape-endowed joint to be formed by virtue of fit byintroducing a joining mass between the connecting element and the endrecess. Furthermore, by shape-endowed design of the end recess and theconnecting element is always to be understood the shape-endowed designof both of these parts with the connecting element set into thegroove-like recess, so that in terms of the shape-endowed design of theconnection, apart from the end recess, only the part of the connectingelement that projects beyond the longitudinal flange of the secondsection is affected.

In a preferred example of the connection according to the invention ajoining mass for sealing the joint or for creating an exact connectionbetween the connecting element and the end recess by virtue of shape isprovided between the connecting element and the end recess in the firstlongitudinal section and/or between the connecting element and thelongitudinal flange on the second longitudinal section.

The joining mass may e.g. be an adhesive mass, a seal, a filler or aweld, braze or solder seam. The adhesive mass may be e.g. an acrylic orcyanide type adhesive, or a single or two component polyurethane orepoxy adhesive. Seals may be of natural materials such as cork or thelike or of plastics or elastomers such as rubber, caoutschouc orthermoplastics. Fillers are e.g. sealing masses based on bitumen,plastic or oil based materials; after a length of time these harden to amore or less elastic mass, at the same time retaining a certain amountof plasticity. A weld seam may be created e.g. by fusion welding,welding via electric gas discharge, electro-beam welding, laser weldingor by metal inert gas (MIG) welding or tungsten inert gas (TIG) welding.

The connecting elements may in principle be of any design complementingthe end recess. Preferred connecting element bodies are for exampleoblique or straight rectangular blunted pyramids and oblique or straightcylinders with e.g. a rectangular base area and at the same time inparticular a body in the shape of a spade or parallelepiped. The side ofthe connecting element set into the groove-like recess is designated thebase, the opposite face the top and the sides of the connecting elementfacing the wall sides of the second longitudinal section as end faces onthe wall side and the sides lying in the direction of the groove-likerecess as the end faces on the connection side. The top surface of theconnection element may be flat or bulging and may come to lie parallelto the base or inclined with respect it.

The height of the end faces of the connecting element on the wall sideis usefully greater than the height of the corresponding longitudinalflange on the second longitudinal section. The height of the connectingelement end face on the wall side in question is preferably greater byat least 1.5 mm, in particular 1.5 to 4.5 mm, greater than the height ofthe corresponding longitudinal flange. This difference in height betweenthe connecting element and the corresponding longitudinal flange ishereinafter referred to as the extra height of the connecting element.

If the height of the end flange is less than the extra height of theconnecting element, then the first longitudinal section is supported atleast partly by the end faces of the section struts, strips orlongitudinal flanges on the top face and/or the end faces of theconnecting element. If the height of the end flanges is greater than theextra height of the connecting element, then the first longitudinalsection is supported by the end faces of the wall sides or the endflanges of the cross-cut longitudinal section are supported on thelongitudinal flanges of the longitudinal section.

The connecting elements may be e.g. of steel, plastic or light metalssuch as aluminum or its alloys. The connecting element is preferablymade of the same material as the longitudinal sections or out of amaterial with a similar coefficients of thermal expansion as thelongitudinal sections. To improve the tightness of the seal at theconnection according to the invention, the material for the connectingelement may if desired be selected such that the smallest possiblethermomechanical stresses arise between the connecting element and thejoining mass to be employed.

The connecting elements may be manufactured e.g. by casting, extrusionmolding or forging. The final shape may be achieved e.g. bychip-forming, mechanical processes such as milling.

The breadth of the connecting elements may be selected such that theycan reside in the groove-like recess with sliding fit, or they may besecured in place in the groove-like recess e.g. by clamping, plugging,wedging, clipping in, by latch fit, bracing, screwing, riveting or bysoldering, welding or adhesive bonding.

The faces of the connecting element on the wall side may run parallel tothe wall sides of the longitudinal sections, the breadth of theconnecting element being e.g. 5 to 100 μm smaller than the distancedefined by the end flanges of the first longitudinal section.

In order to ensure a tight connection is achieved, the length of theconnecting element at the top face is usefully the same as the length ofthe end face of the first longitudinal section.

In a preferred version of the connection according to the inventionangle pieces are introduced into at least part of the groove-like recessin the longitudinal sections in order to provide reinforcement for theconnecting sides of the longitudinal sections; each angle piece featurestwo arms at an angle to each other and each arm is secured by at leastone clamp-screw connection means to the related connecting side of thelongitudinal section; each screw engages in a thread of a retainingelement such as e.g. a clamping platelet that can be introduced from thefront into the undercut groove and each arm of the angle piece exhibitsat least one hole to accommodate the screw(s) engaging in the thread(s)of the clamping platelet(s).

The arms of the angle piece may also exhibit a spring-like integralprojection that can be introduced into the undercut groove of thelongitudinal section.

The clamp-screw connections may already be secured in place on thecorresponding angle piece arms before introducing the angle piece intothe groove-like recess in the longitudinal sections. On fitting thelongitudinal sections together with the angle piece, the springs of theangle piece are pushed into the undercut groove in the longitudinalsection and the clamping pieces introduced in the longitudinal directioninto the groove opening. As the clamping platelet features a threadedhole in which a screw passing through the angle piece engages itself,the platelet can be tilted into the undercut region simply by turningthe screw. The thickness of the arms of the angle piece can be chosensuch that holes for the screws can be countersunk and screws withcountersunk heads employed. The thickness of angle piece necessary forthis may also be achieved by means of a pronounced spring-likeprojection. The clamp-screw connection is therefore tightened solelyfrom the outer side of the angle piece so that no counter-holding toolis necessary for the clamping platelet.

The clamping platelets may exhibit on the side facing the strips on thelongitudinal sections, wedging faces that correspond to wedging areas onthe section strips. On tightening the clamping platelet the plateletcentres itself by mutual contact and possibly by the sliding movement ofthe wedge faces of clamping platelet and section strips.

The clamping platelets may be e.g. in the form of a parallelogram, thelarger diameter of the clamping platelet being greater than the width ofthe longitudinal groove. Consequently, when the clamping screw istightened, the clamping platelet becomes wedged automatically to theinner wall of the longitudinal groove, with the result that rotation ofthe clamping platelet is prevented.

A specially preferred version of the connection according to theinvention is achieved in that the faces of the connecting element on theconnection side exhibits a shape that correlates congruently to the bendin the angle piece i.e. a shape that fits to the rounded form or a shapethat is complementary to the curve on the angle piece.

In a preferred version the connecting element is in the form of aU-shaped longitudinal section with downward projecting flanges. SuchU-shaped connecting elements can be arranged with downward projectingflanges on the section strips of the second longitudinal section or withthe top face on the section strips.

In another preferred version the connecting element exhibits on its basea spring-shaped projection that can be introduced into the undercutgroove of the second longitudinal section.

In a further preferred version the connecting element exhibits a grooveon both wall side faces so that the connecting element with said groovecan be pushed into the undercut groove formed by the section strips inthe second section.

The connecting element may also exhibit lug-shaped projections on itsfaces adjacent to the wall sides. As a result this increases the surfacearea, in particular the surface area available transferring forces fromone longitudinal section to the other.

In order that other structural elements than longitudinal sections maybe attached to the connection according to the invention, a furtheradvantageous version of the connecting element may be such that abulge-shaped projection is provided on one of its wall side faces and anintegral support bracket on the other, opposite-lying wall side face.The bracket may for example exhibit one or more attachment openings.Forces acting on the component attached by means of the bracket and theconnection according to the invention are transferred directly into theconnection.

The invention relates also to a process for manufacturing the connectionaccording to the invention in which a connecting element is introducedinto the groove-like recess of the second longitudinal section and ispositioned at the intended place in the second longitudinal section, theangle piece(s) pushed into the groove-like recess and temporarilysecured in place, the whole of the thus prepared connection providedwith a connecting mass and the first cross-cut longitudinal sectionpushed into the free-standing arm of the temporarily fixed anglepiece(s) and the angle piece(s) permanently affixed to the longitudinalsection that is to be attached by tightening the clamp-screwconnections. A connection made this way may be subjected to mechanicalloading immediately after it has been made as the forces acting on alongitudinal section are transmitted to the other longitudinal sectionvia the angle piece.

The connections according to the invention are particularly suitable forthe assembly of frame structures out of longitudinal sections, forexample for the superstructures of road or railway vehicles or for theassembly of other superstructures out of longitudinal sections e.g.cabins for operators of cranes, farming or municipal transport vehicles.such superstructures made up of frame-like structures are normally stillclad with further structural parts such as steel or aluminium sheet,glass segments or panels made of plastic. In addition, such a frame-typestructure may be closed on the outside e.g. with doors. An interior orexterior cladding may be attached e.g. by means of screws, rivets oradhesive bonding or interlocking hook-type fastener parts. Theinterlocking hook-type fastener parts may be laminated on or adhesivelyattached.

FIG. 1 shows a perspective view of a connection according to theinvention between a first transverse-cut longitudinal section 10 and, atright angles to section 10, a second longitudinal section 22. Thelongitudinal sections exhibit on each of two facing sides, theconnecting sides 12, an undercut groove 24 on both sides, each with alongitudinal opening 26 and on both sides of the groove a longitudinalflange 30. Projecting strips 28 are formed as a result of the undercutgroove. The groove-like recess 34 in the second longitudinal section 22formed by the projecting strips and the longitudinal flange serves toaccommodate and align the connecting element 60 and the angle piece 40.The section strut 32 is situated a distance from the projecting strips28. The cross-sectional end of the second longitudinal section 22 whichis to be joined to the first longitudinal section 10 features a recess18 which is designed such that it connects by virtue of fit to theconnecting element 60.

The connecting element 60 shown in FIG. 1 features on the base 61 of theconnecting element 60 an integral spring 62 which engages in thelongitudinal opening 26 of the undercut groove 24. The base 61 of theconnecting element 60 is supported by projecting strips 28 of thelongitudinal section 22. Further, the connecting element 60 is alignedin the longitudinal opening 26 of the longitudinal section 22 by meansof the spring 62.

The connecting element 60 mounted in the longitudinal section 22projects a height a over the outer edge of the longitudinal flange 30 onsection 22, the height a amounting to the difference in the heights ofthe connecting element 60 and the longitudinal flange 30. The recess 18at the end of the longitudinal section 10 concerns the projecting strips28 and the struts 32 in the end region of section 10. As a result ofthis recess 18, end flanges 20 are formed at the wall sides 14 of thelongitudinal section 10. If the height of the end flange 20 is less thanthe extra height a of the connecting element 60, then the firstlongitudinal section 10 is supported at least in part by the end facesof the struts 32 and strips 28 created by the recess 18, viz., supportedon the top surface 63 of the connecting element 60. If the height of theend flange 20 is greater than the extra height a of the connectingelement 60, then the first longitudinal section 10 is supported by theend flange 20 on the longitudinal flange 30 of the longitudinal section22.

In the connection shown in FIG. 1 the longitudinal sections 10, 22 thatare joined by means of the connecting element 60 are secured in amechanically rigid manner by two angle pieces 40. The angle pieces 40shown in FIG. 1 are in width exactly the same as the distance betweenthe flanges 30. The angle pieces 40 may also exhibit (not shown here) aspring-like part on their arms 42 which engages in the longitudinalopening 26 of the undercut groove 24. In the case of the angle piece 40shown in FIG. 1 the thickness of the arms 42 corresponds to the heightof flange 30 so that the upper edge of the arms 42 lie flush with theupper edge of the longitudinal flange 30. Connecting mass 54 shown inFIG. 1 may be provided for sealing the joint or to achieve an exact fitmechanical joint between the connecting element 60 and the end recess 18between the connecting element 60 and the end recess 18 of the firstlongitudinal section 10 and/or between the connecting element 60 and thelongitudinal flange 30 of the second longitudinal section 22.

Each arm 42 of the angle piece 40 is attached to the correspondingconnecting sides 12 of the longitudinal sections 10, 22 by means of twoclamp-screw connections. Each arm 42 features therefore two holes 44that are spaced apart and are provided to accommodate screws that engagein the threads of clamping platelets.

The interaction of the end flange 20 and the connecting element 60provides the connection with sideways stability and permits forcesacting sideways on one section to be transferred to the othersection--even in the case of thin-walled longitudinal sections. Afurther essential element of the connection according to the inventionis that the interaction of the connecting element 60 with the end flangepermits comer connections to be fabricated that are covered at the sidesand thus the production of frame-type structures e.g. for vehicles.

FIG. 2 shows an explosive view of the object shown in FIG. 1. Bothlongitudinal sections 10 and 22 have the same appearance and exhibit twowall faces 14 and two connecting sides 12, the connecting side 12 beingformed by an undercut groove 24 which is undercut on both sides andfeatures a longitudinal opening 26. Strips 28 are formed by the undercutgroove 24. On each connecting side 12 a distance from the strips 28 arestruts 32 on each which join the wall sides 14 to each other and closeoff the undercut groove 24 on the side away from the longitudinalopening. The parts of the wall sides 14 standing up from the strips 28form the longitudinal flanges 30. The distance between the flanges 30 insection 10 is the same as that in section 22.

The faces 66 of the connecting element 60 on the side towards the walls14 run e.g. parallel to the wails 14 of the longitudinal sections 10, 22or the connecting element 60 has e.g. a blunted cone shape such that thebreadth of the connecting element 60 tapers from the base 61 towards thetop surface 63. The breadth d of the connecting element 60 is smallerthan the spacing between the longitudinal flanges 30; the connectingelement is therefore displaceable on the section strips. The faces 64 ofthe connecting element 60 on the connecting side is of such a shape thatit can fit by virtue of shape to the defined rounding of the bend in theangle piece i.e. the said faces 64 of the connecting element 60 aredomed concave inwards, and the radius corresponds to that of the anglepiece. As a result of the concave shape of the end faces 64, theconnecting element 60 exhibits a top face 63 which is shorter than thebase 61. The length of the top face 63 corresponds usefully to thebreadth f of the end 16 of the transversely cut section 10. The length cof the base 61 is therefore longer than that of the top surface 63 andis determined by the length of the top surface 63 and the concavecurvature of the face 64 of the connecting element 60. The height of theconnecting element 60 is greater than the height of the longitudinalflange 30 of the longitudinal section 22. The difference between theheight e of the connecting element 60 and the height of the longitudinalflange 30 is designated the extra height a of the connecting element 60.This extra height of the connecting element 60 is preferably more than1.5 mm and, in particular, between 1.5 and 4.5 mm. The connectingelement 60 shown in FIG. 2 exhibits additionally on its base 61 anintegral spring 62, which fits into the longitudinal opening 26 of theundercut groove 24.

The transversely cut longitudinal section 10 exhibits an end recess 18which affects the strips 28 and the struts 32 of the section 10 in theregion of the end face 16 i.e. essentially the whole of the end regionbetween the wall sides 14 of the longitudinal section 10, as aconsequence of which free standing ends of the wall sides 14, the socalled end flanges 20 are produced in the end region of section 10. Theheight b of the end flanges is preferably 2 mm or more, in particular 2to 5 mm, so that the section 10 is supported by its end flanges 20 onthe longitudinal flanges 30 of section 22.

As shown in FIG. 2 are two angle pieces 40 for mechanically securing thelongitudinal section 10 positioned by the connecting element 60. Theangle pieces 40 exhibit two arms 42 at an angle to each other, each arm42 featuring two holes 44 that are spaced apart and are for screws 50.The breadth of the arms 42 is less than the distance between thelongitudinal flanges 30 so that the angle pieces 40 can be introducedinto the groove like recesses 34 on the connecting sides 12. Thethickness of the arms 42 is preferably chosen such that the arm 42 liesflush with the upper edge of the flange 30.

The attachment of the angle pieces is preferably performed via twoclamp-screw connections per arm 42, the screws 50 each engaging in thethread of a clamping platelet introduced from the front into theundercut groove 24. The arms 42 of the angle piece 40 may also featurespring-like projections that can be introduced into the longitudinalopenings 26 of longitudinal sections 10, 22.

FIG. 3 shows exemplified embodiments of connecting elements 60. Theconnecting element 60 shown in FIG. 3a exhibits, on both wall side faces66, grooves 69 and lobe-shaped projections 68. This design of connectingelement 60 permits high load transfer from one longitudinal section tothe other. The grooves 69 are designed in such a manner that theconnecting element 60 can be introduced into recess 34 of section 22with the grooves 69 accommodating the strips 28 of the undercut groove24 of section 22. The lobe-like projections 68 provide additionalsideways stability to connection according to the invention.

The connecting element 60 shown in FIG. 3b exhibits a simple U-shapedcross-section with flange 67. Such a connecting element 60 may beemployed with the flanges on the strips 28 on the longitudinal section22 or inverted i.e. with the top surface 63 on the section strips. Theheight e of the connecting element 60 is designed such that when theconnecting element 60 is situated in the recess 34 in the longitudinalsection 22, it projects at least 2 mm above the corresponding upper edgeof the longitudinal flange 30.

The connecting element 60 shown in FIG. 3 c) exhibits a bulge shapedprojection 70 on a face 66 that is directed at the wall side of thelongitudinal sections, and on the opposite side an integral supportingbracket 72 with an attachment opening 74 to accommodate e.g. screws,rivets, bolts or clamping wedges. In a connection according to theinvention employing such a connecting element 60, both projections onthe wall side come to rest between the end flange 20 on the cross-cutsection 10 and the corresponding longitudinal flange 30 on section 22.The bracket 72 serves to secure other components e.g. by means ofscrewing, riveting, clamping, soldering, welding or adhesive bonding,and permits these components to transfer a load directly into theconnection according to the invention.

The connecting element 60 shown in FIG. 3 d) exhibits a spring 62 thatcan be introduced into the longitudinal opening 26 of section 22. Alsoshown--instead of the clamping platelet--is a continuous clamping strip76 for joining the arms 42 to the longitudinal section 22.

FIG. 4 shows side views of connections according to the inventionfeaturing different shapes of connecting elements 60. In all of the sideviews shown the cross-section of longitudinal section 22 is at thebottom and a section through the longitudinal section 10--showing onlythe wall faces 14--is in the upper part of the figure. The side view ofsection 22 corresponds to its short cross-section so that the undercutgrooves 24 with longitudinal opening 26 and inward projecting flanges30, struts 32 and strips 28 can be recognized.

The connecting element 60 shown in FIG. 4 a) exhibits two lugs 78 thatcan be introduced into the longitudinal opening 26 of the undercutgroove 24. Such integral lugs 78 on the connecting element 60 areparticularly suitable for clipping the connecting element 60 into theundercut groove 24.

FIG. 4 b) shows a connection with groove 69 and lobe-shaped projections68 on the connecting element 60, and shows therefore in side view theconnection of a pair of longitudinal sections 10, 22 made using aconnecting element 60 as shown in FIG. 3 a).

FIG. 4 c) shows the side view of a connection according to the inventionusing a U-shaped connecting element 60, which is mounted with itsflanges 67 on the strips 28 of section 22. Flanges 67 connect thelongitudinal flange 30 of section 22 to the end flange 20 of section 10.

FIG. 4 d) shows the side view of a connection according to the inventionbetween a pair of longitudinal sections 10, 22 employing a connectingelement 60 that exhibits a groove 69 on each of its sides facing thewalls, the said groove 69 having such a shape that the connectingelement 60 can be introduced into the undercut groove 24. The connectingelement 60. The connecting element 60 is introduced into section 22 withits grooves 69 accommodating the strips 28 of section 22. Forces actingsideways or vertically onto the connecting element 60 are thereforetaken up by the groove/section-strip connection and transferred to thelongitudinal section 22.

FIG. 4 e) represents a side view of a connection according to theinvention employing a connecting element 60 as shown in FIG. 3 c). Theconnecting element 60 exhibits a bulge-shaped projection 70 and, on theopposite side an integral bracket 72. In the version shown in FIG. 4 e)the base 61 of the connecting element 60 is supported by the strips 28on section 22. In this version the projections 70, 72 on the wall sidecome to rest between the end side flange 20 of the cross-cut section 10and the longitudinal flange 30 of longitudinal section 22.

In a connection made according to the present invention between alongitudinally profiled section and the end face of a secondlongitudinal section situated at an angle to the first mentioned sectionthe transfer of forces from one longitudinal section to the other takesplace essentially by way of the connecting element, by means of whichoptimum transfer of forces is assured, especially when employingthin-walled sections.

Furthermore, the connection according to the invention makes it possibleto join a pair of longitudinal sections at an angle to each otherwithout elaborate working of the end face of the cross-cut section, asthe connection according to the invention no longer requires a cleandividing line on the cross-cut section.

Also, the connection according to the invention make it possible tomanufacture a tight connection between the sections that are joined, asthe connecting element provides a contact interface large enough for aconnecting mass to be applied.

We claim:
 1. Connection structure which comprises: connection of twolongitudinal sections that are at an angle to each other, eachlongitudinal section having two connecting sides and two wall sides,where at least one connecting side of each section exhibits between thetwo side walls a groove that is undercut on both sides and defines onboth sides of the undercut groove an integral longitudinal flange and asection strip which forms a groove-like recess; wherein the firstlongitudinal section is cut transversely and the cross-cut section faceforms an end face of the first longitudinal section which is secured atan angle to a connecting side of the second longitudinal section; andwherein the first longitudinal section exhibits a recess at its end,said recess extending over the entire length of the end face of each ofthe two wall sides and from said end face to an end of said sectionstrips of said first longitudinal section; and a connecting element,that is introduced into the groove-like recess between the longitudinalflanges in the second longitudinal section, and which engages in thisrecess, as a result of which the connecting element forms a mechanicaljoint by virtue of fit with the end recess.
 2. Connection according toclaim 1, including a connecting mass for at least one of sealing thejoint and to achieve an exact fit mechanical joint between theconnecting element and the end recess provided between the connectingelement and the end recess of the first longitudinal section. 3.Connection according to claim 2, including a connecting mass for atleast one of sealing the joint and to achieve an exact fit mechanicaljoint between the connecting element and the end recess provided betweenthe connecting element and the longitudinal flange of the secondlongitudinal section.
 4. Connection according to claim 1, wherein thewall sides of the first longitudinal section include end flangesadjacent said recess, wherein said end flanges exhibit a height of atleast 2 mm.
 5. Connection according to claim 4, wherein said height isbetween 2 and 5 mm.
 6. Connection according to claim 1, wherein theconnecting element includes wall side faces adjacent the longitudinalflanges of the second longitudinal section, and wherein the height ofeach wall side face of the connecting element is greater by at least 1.5mm than the height of the longitudinal flange of the second longitudinalsection.
 7. Connection according to claim 6, wherin the height of eachwall side face of the connecting element is greater by 1.5 to 4.5 mm. 8.Connection according to claim 1, wherein the connecting element has atop surface, and wherein the top surface of the connecting elementexhibits a length which corresponds to the length of the end face of thefirst longitudinal section.
 9. Connection according to claim 1, wherein,in order to reinforce the connection, insertable angle pieces areprovided between the connecting sides of the longitudinal sections inthe groove-like recess in the sections, each angle piece exhibiting twoarms at an angle to each other to define a curvature, and each arm ofthe angle piece is attached by at least one clamp-screw connecting meansto the longitudinal sections where each screw engages in a thread in aclamping platelet that is introduced into the undercut groove, and eacharm of the angle piece exhibits at least one hole to accommodate atleast one screw that engages in the threads of the clamping platelets.10. Connection according to claim 9, wherein the connecting elementincludes connecting side faces and wherein the connecting side faces ofthe connecting element exhibit a form that is congruent in a correlativemanner with the curvature of the angle piece.
 11. Connection accordingto claim 1, wherein, the connecting element is in the form of a U-shapedlongitudinal section.
 12. Connection according to claim 1, wherein, theconnecting element exhibits on its base a spring-shaped projection thatcan be introduced into the undercut groove of the second longitudinalsection.
 13. Connection according to claim 1, wherein the connectingelement includes two wall side faces and wherein the connecting elementexhibits a groove on both wall side faces so that the connecting elementcan be inserted with the aid of its groove into the section stripsformed by the undercut groove in the second longitudinal section. 14.Connection according to claim 1, wherein the connecting element includeswall side faces, and wherein the connecting element exhibits lobe-shapedprojections on its wall side faces.
 15. Connection according to claim 1,wherein the connecting element includes two wall side faces oppositeeach other, and wherein the connecting element exhibits a bulge-shapedprojection on one of its wall side faces and an integral supportingbracket on the opposite wall side face.